The application of animal models in the research of infectious human diseases is critical to the development of safe and efficacious treatment protocols and preventative medications and biologicals. The goal of the candidate is to obtain research skills and knowledge essential for an ongoing and productive research career in the areas of veterinary virology and immunology as they apply to the understanding of infectious human diseases. Under the current proposal, during Phase I, the candidate will participate in a program of coursework followed by research leading to a Ph.D. in Veterinary Microbiology during Phase II. The specific research goal is to examine the lentivirus feline immunodeficiency virus (FIV) with regard to the ability of defined structural polyproteins and proteins to induce cell-mediated immunity as demonstrated by in vitro T-cell proliferative responses and lymphokine production, in particular interleukin 2 (IL2) production. Other lymphokines under consideration for investigation include interferon and tumor necrosis factor(TNF) lymphotoxin (LT). These proliferation and lymphokine studies will be done in conjunction with an ongoing project using retroviral and baculoviral vectors to express recombinant viral antigens in target T cells to evaluate responses by cytotoxic T-ceIls to specific viral proteins. In addition, humoral immunity will be examined in cats inoculated with viral proteins, with special attention to neutralizing antibodies. The long-term objective is to develop a subunit vaccine which induces protective cell mediated immunity against lentiviral associated acquired immune deficiency syndrome. This proposal will address defining FIV structural polyproteins and individual proteins and identifying immunodominant epitopes that may be critical in enhancing helper T cell imm ity. This candidate will initially work to incorporate the env polyprotein, which has been cloned into the TA Cloning vector, into the baculovirus protein expression system. Concurrent efforts will be directed at purification of the FIV gag polyprotein (p49) which has already successfully been established in baculovirus cultures.Subsequent efforts will involve looking at the individual env proteins (gp lOO, gp36) and gag proteins (p10, p 17, p24) for their ability to induce helper T cell activity. Finally, in the Phase II segment of this study, immunodominant epitopes of the structural proteins will be evaluated in the same systems.